Automatic ignition mechanism for gas burners



May 8, 1956 J. M. HOFF 2,745,042

AUTOMATIC IGNITION MECHANISM FOR GAS BURNERS Filed July 14, 1952 INVENTOR.

Jo/m N. Hoff flm. Judi/Z1 United States Patent AUTOMATIC IGNITION MECHANISM FOR GAS BURNERS John M. Hoff, Mansfield, Ohio, assignor to The Tappan Stove Company, Mansfield, Ohio, a corporation of Ohio Application July 14, 1953, Serial No. 367,833

3 Claims. (Cl. 31783) This invention relates to an automatic ignition mechanism for the top burner of cooking ranges using gaseous fuel.

Heretofore automatic ignition mechanisms of this general type usually included a gaseous fuel pilot burner which was remote from the main burner and was supplied with fuel through a separate conduit which was independent of the main burner. The valve which controlled the supply of fuel to the main burner also controlled the supply of fuel to the pilot burner and was therefore necessarily more complicated and expensive than a valve which controlled only the supply of fuel to the main burner. When turned on the pilot burner was ignited by an electric resistance element and the pilot burner in turn ignited the main burner through a flash tube which extended between the pilot burner and the main burner.

My new and improved ignition mechanism enables me to eliminate the pilot burner, the supply conduit therefor, the flash tube, and the complicated control valve, thus providing a much simpler and a much less expensive, but nevertheless a very efiicient automatic ignition mechanism.

In accordance with my invention I provide the main burner with a single jet which extends outwardly from the side of the burner below the main jets, and I mount an electric resistance ignition element in close proximity to the discharge end of the jet. When turned on the electric ignition element ignites the side jet and it in turn ignites the main jets of the burner. The electric ignition element is carried by a block of insulating material in series with a normally closed thermally responsive switch which is also mounted upon the block of insulating material. The thermally responsive switch comprises two normally engaging contacts, one of which is carried by a fixed stationary arm and the other of which is carried by a movable arm which is adapted to flex and move the contact carried thereby out of contact with the othercontact when heat is applied thereto. The movable arm is disposed above the electric ignition element in position to be heated by the small flame from the side jet after it has been ignited by the electric ignition element. The thermally responsive switch is disposed in series with a normally open switch which is adapted to be closed by the opening of the burner control valve and to be opened by the closing of the burner control valve. in operation the burner control valve is manually opened, to supply fuel to the burner, which simultaneously closes the normally open switch and effects the energization of the electric ignition element which then ignites the side jet which in turn ignites the main jets of the burner. After the movable arm of the normally closed switch has been sufiiciently heated by the flame from the side jet it will flex and open the normally closed switch and thereby break the circuit to and de-energize the electric ignition element. The burner will remain ignited until the fuel supply therefor is cut olf by the closing of the control valve. If the side jet should be extinguished for any CIl 2,745,042 Patented May 8, 1956 reason during the operation of the burner the movable arm will cool and close the thermally responsive switch which will effect the re-energization of the electric ignition element which will then re-ignite the side jet.

The principal object of the invention is to provide a very eificienhsimple and inexpensive automatic ignition mechanism for the top burner of cooking ranges;

Other and more limited objects of the invention will be apparent from the following specification and the accompanying drawings forming a part thereof in which:

Fig. l is a diagrammatic layout showing my invention applied to a top burner of a cooking range;

Fig. 2 is an enlarged vertical sectional view taken on the line 22 of Fig. 1; and

Fig. 3 is an enlarged vertical sectional view taken on theline 33 of Fig. 1.

Referring now to the drawings by reference characters the numerals 1 and 2 are applied to the front and one side wall respectively of a cooking range, and the numeral 3 to one of the top burners therefor. Gas is supplied to the burner 3 through its mixing tube 4 from a fuel supply manifold 5. A cut-off valve 6 which is adapted to be manually opened and closed by a handle 7 and valve stem 8 is provided to control the supply of fuel to the burner 3.

The burner 3, as shown herein, is generally ring-shaped and has a plurality of main jets or orifices 10 arranged in an annular row in the bevelled surface 11 adjacent 21 also carries an electric resistance ignition element 24' the top of the burner, and an auxiliary jet or orifice 12 which extends radially outwardly from the side of the burner below the annular row of main jets 10. When fuel is supplied to theburner 3, by the opening of the valve 6, the auxiliary jet 12 is automatically ignited by an electric ignition mechanism generally indicated by the numeral 14, and the main jets .10 are ignited by the auxiliary jet 12. i

The electric ignition mechanism 14 comprises an arm 15 of suitable insulating material which is adjustably secured by bolts 16 to a bracket 17' which is secured to the side wall 2 as indicated at 18 and extends inwardly therefrom. The free end of the arm 15 has a pair of vertically disposed electric connector sockets 19 and 20 suitably secured therein. A block 21 of suitable insulating material has a pair of vertically disposed connector prongs 22 and 23 mounted therein, which extend down below the block 21 and are adapted to be removably seatedin the sockets 19 and 20 respectively. The block and a normally closed thermally responsive switch generally indicated by the numeral 25.

The switch 25 comprises a stationary contact 26, which is secured to a conductor arm 27 carried by the block 21, and a movable contact 28 which is secured to the free end of a horizontally disposed bimetallic conductor arm 29, the other end of which is connected to the upper end of the prong 22. The electric resistance ignition element 24 which consists of a short helical coil of fine wire has one end connected to the conductor 27, as indicated at 30, and the other end thereof connected to the projecting upper end of the prong'23 as indicated at 31.

A normally open switch having the terminals 36 and 37 is mounted adjacent the valve 6 and is adapted to be opened and closed by a cam 38 carried by the valve stem 8 through the medium of a plunger 29. The arrangement is such that the switch 35 is simultaneously closed with the opening of the valve 6 and is simultaneously opened with the closing of the valve 6. The terminal 26 is connected to the socket 19 by a lead 40 and-the terminal 37 is connected to one side of the secondary winding 41 of a transformer 42 by a lead 43.

The other side of the secondary winding 41 is connected to the socket by a lead 44. The primary winding 45 of the transformer is connected to the house line 46-4-7 by the leads 48 and 49.

In operation the valve 6 is manually opened by the turning of the handle 7 and valve stem 8, to supply gas to the burner 3. The opening of the valve 6 simultaneously closes the normally open switch 35. Current then flows from one side of the secondary winding 42 through the lead 43, switch 35 and lead 49 to the socket 19. From the socket 19 the current flows through the prong 22, arm 29, contacts .28 and 26, conductor arm 2'7 and electric resistance element 24 to the prong 23, and from the prong v23 the current flows back to the other side of the secondary winding through the socket 2G and lead 44. This energizes the ignition element 24 which then ignites the auxiliary jet 12 which in turn ignites the main jets 10 of the burner 3. After being ignited the jet 12 projects a fiame against the bimetallic arm 29.

After the arm 29 has been sufiiciently heated it will flex r and separate the contacts 26 and 28 which will break the circuit to and deenergize the ignition element 24. To terminate operation the valve 6 is closed and the switch 35 simultaneously opened by the handle 7 and valve stem 8. the supply of gas thereto the arm 29 will cool and close the switch 25. The mechanism is then in condition for the next operation thereof.

if the ignition element 24 burns out or the switch becomes inoperative for any reason, the block 21 may be removed and discarded and another block 21 having an unimpaired ignition element and switch substituted therefor.

From the foregoing it will be apparent to those skilled in this art that I have provided a very simple, efiicient and inexpensive mechanism for automatically igniting a cooking range burner whenever the control valve therefor is opened to supply gas thereto.

It is to be understood that I am not limited to the specific construction shown and described herein as various modifications may be made therein within the scope of the appended claims.

What is claimed is:

1. A combined electric ignition means and a thermally responsive control switch therefor which is adapted to be removably mounted in a cooking range in position to ignite a gaseous fuel burner and comprises, a base of insulating material, a first connector prong carried by said base, a conductor arm carried by said base, a second connector prong carried by said base, said prongs extending above and below said base with the lower ends After the jet 12 is extinguished by cutting otf thereof being adapted to he received in a socket, a thermally responsive arm secured to the upper end of said first prong and extending outwardly therefrom substantially parallel to said base, a stationary contact carried by said conductor arm, a movable contact carried by said thermally responsive flexible arm in engagement with said stationary contact, and electric ignition means connected between said conductor arm and said second prong, said means thereby being in circuit with and controlled by such contacts, said thermally responsive flexible arm being operative when heated to move said movable contact out of engagement with said stationary contact.

2. A combined electric ignition means and a thermally responsive control switch therefor as defined in claim 1 in which said electric ignition means comprises a helical coil of fine electric resistance wire having one end thereof connected to said conductor arm and the other end thereof connected to said second prong.

3. A combined electric ignition means and a thermally responsive control switch therefor which is adapted to be removably mounted in a cooking range in position to ignite a gaseous fuel burner and comprises, a base of insulating material, a first prong and a second prong carried by said base with the upper ends thereof disposed above said base and the lower ends thereof disposed below said base and adapted to be received in a socket, a conductor arm carried by said base, said prongs and said conductor arm being disposed in longitudinal alignment with each other with said second prong disposed between said first prong and said conductor arm, a thermally responsive flexible arm secured to the upper end of said first prong and extending outwardly therefrom substantially parallel to said base above said second prong and said conductor arm and in vertical alignment therewith, a stationary contact carried by said conductor arm, a movable contact carried by said thermally responsive flexible arm in engagement with said stationary contact, and an electric ignition element disposed under said thermally responsive flexible arm and comprising a helical coil of fine electric resistance wire having one end thereof connected to said second prong and the other end thereof connected to said conductor arm, said thermally responsive flexible arm being operative when heated to move said movable contact out of engagement with said stationary contact.

References Cited in the file of this patent UNITED STATES PATENTS 

